GM’s E-Flex electric vehicle architecture took a step forward as the automaker announced it would partner with A123Systems (www.a123systems.com; Watertown, MA) to develop lithium-ion battery cells for use in the Chevrolet Volt, which is expected to hit the market in late 2010. This agreement puts a bit more credibility to the plans to get the plug-in hybrid on the streets because A123’s unique nanophosphate battery chemistry is presently used in millions of Black & Decker cordless power tools. “We’re already the world’s largest producer of this nanophosphate chemistry,” Ric Fulop, one of the founders and vice president of business development of A123, says while pointing out his company produces more than 10 million cells each year from its production facilities in China.
What makes A123’s batteries so unique? Unlike traditional oxide-based lithium-ion batteries—which use volatile materials including lithium, nickel, cobalt and aluminum oxide—A123’s system, developed in the labs of the Massachusetts Institute of Technology, relies on lithium iron phosphate (Li-Fe), which is less volatile. Likewise, the use of nanotechnology allows A123 to scale particle size below 100 nm, providing faster kinetics and higher power densities. “The benefit of this chemistry is that it forms a covalent bond that is extremely strong and stable and will not release oxygen if exposed to an elevated temperature, like traditional lithium-ion systems,” Fulop explains.
Other key benefits are transporting and recyclability. According to United Nations regulations, lithium ion batteries must be treated as Class 9 grade hazardous materials during transport. In some cases, the cells have to be shipped in explosive-proof drums. David Vieau, president and CEO of A123 says his company’s chemistry complies with U.N. regulations and does not require any significant safeguards, and since the batteries use little volatile chemicals, their recyclability is improved compared with traditional lithium-ion systems. “We wanted to make sure we used materials that are abundant and readily available on the Earth. Our primary components are iron, phosphate and carbon, while the majority of materials used are aluminum and copper, all of which are easily recycled. We don’t have any precious metals or heavy metals so we’re pretty good from end to end.”
While GM has yet to decide what plant will build the Chevrolet Volt, Vieau says A123 plans to manufacture the battery packs within close proximity to whichever location is chosen: “Because of the size and complexity, the majority of these systems for automotive will have to be assembled and produced locally, close to where the vehicle is assembled,” he says.
Asked if there is anything that can derail the battery system’s capability to meet the 10-year durability targets set by GM, Vieau points to packaging as the only major obstacle: “We now have to redesign the battery itself to meet the form factor, shape and capacity in the configuration given for the system.” He’s confident A123 can meet the 2010 production target. Fulop is quick to note that the most complex issue, the chemistry of the battery itself, has already been solved and that’s significant. “The packaging issue is not all that significant although we don’t want to trivialize it, either.”—KMK